Frequency changer



Feb'z, 1940.. I K POSTHUMUS 2,190,731

FREQUENCY CHANGER Filed may 2l. 1957 5 zllllll, 9

|I7II Patented Feb. 20, 1940 UNITED STATES rFur:QUENCY CHANGER KlaasI Posthumus, Eindhoven,.Netherlands, yassignor, by mesne assignments,` to Radio Corporation ..of.America, New tion of `Delaware York, N. Y., acorporar Application May '21, 1937, Serial No. 143,947

` In Germany June 5, 1936 2 claims., (ol. 25o-3c) This invention concerns improvements in or relating to circuits for doubling thefrequency of electric high frequency and ultra-high frequency oscillations.

5* This invention relates to a circuit for multi- `plying the frequency of high frequency and ultra-high frequency oscillations particularly one in which the frequency to be multiplied is doubled by each'` multiplying stage.

In a known circuit of the: said kind the oscillations to be multiplied aresupplied in phase opposition to the grids of two .discharge tubes. The anodes of these tubes are inter-connected and the cathode circuit common to both these tubes includes an impedance which is a high re'- sistance for the doubled frequency.

Such a `circuit has the disadvantage of not being suitedlfor multiplying oscillations half the period of which is less than the transittime of .the electrons inside the discharge tube. This transit time is dependent upon the distance between the cathode and the anode of each discharge tube.

The invention has for its object to provide a 25 circuit suitable for the multiplication of oscillations having a higher 'frequency than is possible with the circuit mentioned hereinbefore.

In the circuit according to the invention two diodes are used the cathodes of which have `supplied to them in phase opposition the oscillations to be multiplied.

The oscillations to be multiplied are, however, preferably supplied to a .discharge tube comprising two cathodes and a common anode.

One embodiment of a tube for use in a circuit according to the invention comprises two parallel linear cathodes which are each surrounded by a narrow tubular anode the axis of which coincides with the corresponding cathode and which contact each other throughout their length.

A further embodiment of a tube for use in a circuit according to the invention comprises two cathcdes surrounded by a commonanode and ar-4 ranged so that when one cathode emits the other has a controlling action on the emission. Such a tube preferably contains two wire-shaped cathodes located in two planes normal to each other 50 and surrounded by a cylindrical anode theaxis of which coincides with the intersecting line of the cathode planes.

` In order that the invention may be clearly understood and readily carried into effect three embodiments thereof will now be described more fully with referenceto the acompanying drawing.

in which. lil, l

Figure 1 shows a known circuit for doubling the frequency of high -frequencyoscillations Figure 2 shows anwembodiment` ofthe circuit l according tothe invention. l

Figures 3 and 4 show circuits according to the invention in which useislmadeofl a particular tube construction. l

Figure 1 shows a circuit comprising discharge tubes I and 3; The grids of the discharge tubes have connected betweenthem an oscillatory circuit 5 to whichthe oscillations tobe multiplied are supplied and which `is tuned to the frequency to be multiplied..` The anode circuit common to both tubes includes a source of anode voltage l' and an oscillatory circuit 9 tuned to double the frequency of the' oscillations to be multiplied.:

In the circuit described the oscillations to be multiplied are supplied in phase opposition.. to i the grids. ofzthe` tubes. l` and 3. The negative bias of the` tubes is supplied from a source of voltage Il the voltage of which is less than the maximum amplitude of the alternating voltage supplied to the tubes. This gives rise in the common anode circuit during each half cycle of the oscillations to be multiplied toa current pulse which excites the circuit 9 at a vfrequency corresponding to twice `the frequency of the oscil lations supplide to the circuit 5. 1

The circuit described is not suitable for multiplying oscillations half the period of which is less than the transit time of the` electrons inside the tube, since in the case of multiplication of such frequencies the electrons emitted from the cathode of one of the tubes do not reach the anode with a positive grid before the grid is again lnegative so that the tube is blocked.

The circuit shown in Figure 2 permits of multiplying oscillations having a higher frequency.

`This. circuit comprises two diodes 2 and All the cathodes of which are interconnected via an oscillatory circuit 5 to which the oscillations to be multiplied are supplied. The anodes of the tubes 2 and 4 are connected to the corresponding cathl ode via a circuit 9 and a source of anode voltage use of the known circuit shown in Figure l.

tel

A discharge tube highly suited for use in the circuit shown in` Figure 2 is shown in Figure 3 in sectional view. This tube contains two linear cathodes 6 and 8 which are parallel to each other and are normal tothe surface of the drawing. The cathodes 6 and 8 are each surrounded by a narrow tubular anode I and I2 respectively, the axis of which coincides with the corresponding cathode. The anodes are so arranged side by side that they contact each other throughout their length. The use of this tube construction in which the length of the electrodes is great compared with the distance of each of the cathodes relatively to the corresponding anode permits of multiplying high frequency oscillations and of obtaining thereby a suflicient output energy. The circuit shown'in Figure 3 is entirely similar to that of Figure 2. f

4Figure 4 shows a circuit in which a discharge tube I4 comprising two cathodes I6 and I8 and a common anode 20 is used for multiplying oscillations. The cathodes I6 and I8 are wire-shaped and` located in two planes normal to each other. Theseplanes are normal to the surface of the drawing. The cathodes are surrounded by a cylindrical anode 20 whose axis coincides with the .intersecting line of the cathode planes and whose length is great compared with the diameter. The cathodes have connected between them an oscil latory circuit to which the oscillations to be multiplied are supplied. The anode 20 is connected to each of the cathodes IB and I8 via an oscillatory circuit 9 tuned to double the frequency Aand a source of anode voltage 'I.

the function of a control grid, since this electrode has supplied to it during this time a positive alternating voltage relatively to the cathode I6. Conversely, the cathode I6 controls the electrons emitted from the cathode I8 during the halfcycle of the oscillations supplied to the circuit 5 in which a higher positive voltage occurs between the anode 20 and the cathode I8 than between the anode 20 and the cathode I6.

A'l'he working of the tube described thus corresponds in regard to amplification to a tube comprising two triode-systems but constructionally the tube only'contains two diodes. It has consequently the advantage that the path which is to be traversed by the electrons during half the period of the oscillations to be multiplied and which is dependent upon the distance of the cathodes I6 and `I8 relative to the anode 20 is small so that compared with a triode it can serve for the multiplication ofl oscillations having a higher frequency..

, I claim:

l. In a frequency multiplying system an electron discharge device comprising a pair of linear electron emission electrodes mounted in planes at right angles to each other, an anode structure surrounding said emission electrodes, means for impressing wave energy the frequency of which is to be multiplied in phase opposition on said linear electrodes, and means for deriving the resultant energy from said anode structure.

A2. A system as recited in claim 1 including means for biasing said anode relative to said emission electrodes by a direct current potential such that when one of said emission electrodes is excited by the impressed Wave energy to emit electrons the other emission electrode serves as a control electrode for said emitting electrode and vice versa.

KLAAS POSTHUMUS. 

